2.过去完成式
1.陈述句：S + had + 过去分词
This proposal had been delivered by Eva before Aaron finished it
2.否定句：S + had + not + 过去分词
I had not finished my work when he visited me last week
3.疑问句：Had + S + 过去分词
Had you (ever) been to a blind data before you married
3.将来完成式
will have to && going to have to
1.陈述句：S + shall/will + have + 过去分词
They will have finished the meeting by now
2.否定句：S + will + have + not + 过去分词
We will have not made 10 apple pies by the end of today
3.疑问句：Shall/Will + S + have + 过去分词
Will they have already left by the time we get there
1.现在完成式（Present Perfect Tense）
1.陈述句：S + have/has + 过去分词
I have already finished my homework.
2.否定句：S + have/has + not + 过去分词
Sandy has been a nurse in this hospital for 15 years.
3.疑问句：Have/Has + S + 过去分词
Have you (ever) seen Peter in past 3 months? 这里ever是曾经的意思可有可无
4.句型
have been
I have been a student for three years
I have been in Beijing for 10 days.
I have been to beijing
I have never been there
have been + n./ have been to + 地名 /have been (to)+ 地点副词
have to
hav to == must 必须/不得不
have got to = have to
过去时had to/现在时have to/未来时will have to
I have to ask my boss first
